Why corrugated metal offered strength without heavy plate

Why was corrugated metal introduced, and how did the idea apply to aviation?

Corrugation let thinner material carry loads with greater structural stiffness, producing a lighter and stronger skin before aluminum became the preferred solution.

Corrugation makes thinner metal structurally stronger without simply adding more material. The formed sheet can resist loads and movement better than a flat sheet of similar thickness. That makes the method attractive in aircraft, where reducing weight while retaining stiffness is especially valuable. It was an approach used before aluminum became the more familiar lightweight solution. Corrugated skin was an engineering choice rather than a stylistic feature.